GPS Adjacent Band Compatibility Assessment

Munich Satellite Summit

March 2017

Objective

2

Collect the necessary data to determine adjacent band transmit power levels that can be tolerated by existing GNSS receivers for civil applications Excludes certified aviation applications that are considered

in a parallel effort conducted by the FAA

Data collected and discussed in this brief: Radiated test data: collected in an anechoic chamber Conducted test data: collected in a laboratory environment Antenna characterization data

o Integrated antennas: collected in an open sky environment o External antennas: collected in an anechoic chamber

Overview

3

Developed GPS/GNSS receiver test plan and test procedures

Held many public workshops to obtain stakeholder input

Coordinated government and manufacturer participation and executed Non Disclosure Agreements (NDAs)

Developed/validated radiated RF test environment

Carried out GPS/GNSS receiver testing and antenna characterization Radiated receiver testing - White Sands Missile Range, NM

Wired (conducted) receiver testing - Zeta Associates , VA

Antenna Characterization – MITRE Corporation

Produced initial 1 dB Interference Tolerance Mask (ITM) results ITM = Interference power (IP) resulting in 1 dB degradation

to carrier-to-noise-ratio (CNR)

4

GPS receiver testing was carried out April 25-29, 2016 at the Army Research Laboratory's (ARL) Electromagnetic Vulnerability Assessment Facility (EMVAF), White Sands Missile Range (WSMR), NM EMVAF – 100’ x 70’ x 40’ Anechoic Chamber

Air Force/GPS Directorate conducted testing week of April 18th

Tests performed in the anechoic chamber: Linearity (receivers CNR estimators are operating in the linear region)

1 MHz Bandpass Noise (Type 1)

10 MHz LTE (Type 2) – Focus of this briefing

Intermodulation (effects of 3rd order intermodulation)

Radiated Testing Overview

Categories of GPS/GNSS Receivers Tested

5

80 receivers were tested representing six categories of GPS/GNSS receivers:

General Aviation (non certified)

General Location/Navigation

High Precision & Networks

Timing

Space Based

Cellular

Participation in Testing

6

Participation included DOT’s federal partners/agencies and GPS manufacturers United States Coast Guard (USCG)

National Aeronautics and Space Administration (NASA)

National Oceanic and Atmospheric Administration (NOAA)

United States Geological Survey (USGS)

Federal Aviation Administration (FAA)

United States Department of Transportation (USDOT)

General Motors (GM)

u-blox

NovAtel

Trimble

John Deere

UNAVCO

GNSS Signals Used in Testing

Signal

GPS L1 C/A-code

GPS L1 P-code

GPS L1C

GPS L1 M-code

GPS L2 P-code

SBAS L1

GLONASS L1 C

GLONASS L1 P

BeiDou B1I

Galileo E1 B/C 7

Interference Test Signal Frequencies and Power Profiles

1450 1460 1470 1480 1490 1500 1510 1520 1530 1540 1550 1560 1570 1580 1590 1600 1610 1620 1630 1640 1650 1660 1670 1680 1690 1700-140

-120

-100

-80

-60

-40

-20

0

Frequency (MHz)

Targ

ete

d R

eceiv

e P

ow

er

(dB

m)

Type 1 & 2

Type 1

Radionavigation Satellite Service (RNSS) Band

8

Chamber Setup

9

Data Processed to Produce a 1 dB Interference Tolerance Mask (ITM)

• Example for determining ITM for 1 frequency (1545 MHz) for PRN 31 for one of the Devices Under Test (DUT)

IP vs. Time

CNR vs. Time

1 (dB)

𝑰𝑻𝑴 𝒇

10

Aggregate Results for L1 C/A High Precision Category

1450 1500 1550 1600 1650 1700-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

Frq (MHz)

IP a

t 1 d

B (

dB

m)

ITM (Low er Bound)

ITM (10th Prctile)

ITM (50th Prctile)

ITM (90th Prctile)

ITM (Upper Bound)

GPS L1 C/A ITM lower bound and different percentiles corresponding to the HPR category.

The lower the ITM percentile the more protection it offers. The bounding ITM (black) protects all tested receivers 11

L1 C/A Bounding Masks Compared With Certified Aviation Mask

1450 1475 1500 1525 1550 1575 1600 1625 1650 1675 1700-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

Frq(MHz)

IP a

t 1dB

(dB

m)

GPS L1CA All Receiver Categories

12

Example Min. Separation Distance vs. Received Power Single Transmitter with Free Space Path Loss

250’

Note: This analysis does not consider receiver antenna pattern and uses transmitter pattern recommended in ITU-R F.1336

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Summary of Bounding Mask Results

A more comprehensive set of results are presented in the paper

L1 C/A Bounding Mask Results for

All Categories of Receivers

HPR Bounding Mask Results for

All Emulated GNSS Signals

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Wired/Conducted Testing Overview

Tests executed week of 25 July with 14 GNSS receivers • Representative set of equipment from chamber testing from each

receiver category (except space based) • Receivers tested were USG provided

Test Objectives • Receiver characterizations for comparison with chamber results • Inclusion of OOB interference at

o FCC limit of -70 dBW/MHz o Proposed limits of -100 (base stations) and -105 (handsets)

dBW/MHz • GNSS signal re-acquisition characterizations

Same test instrumentation for wired as with radiated tests • GNSS playback (MITRE) • Interference system with modifications to support OOBE and

acquisition test requirements 15

Normalizing Interference Power to IP@1dB in the Acquisition Analysis

IP @ 1dB

CNR vs. Interference Power

Acquisition Time vs. Interference Power

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Summary of Acquisition Performance at 1550 MHz

Number of DUTs Average acquisition time for ICD minimum and low

elevation satellites

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Summary and Next Steps

Results: Tolerable interference power in form of bounding ITMs have been developed for

all category of receivers tested on a per GNSS signal type basis

Wired (lab) tests show good consistency with radiated test results when antenna filtering characteristics are taken into account.

1-dB degradation proved to be a good indicator of the onset of acquisition degradation especially for low elevation satellites

Next Steps: Evaluate use case scenarios

Use inverse modeling to transform the bounding masks to allowable transmit power levels for each category

Develop final report

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Backup

Receiver Test List (1/2)

No. Receiver 1 Trimble SPS461 2 Furuno GP-33 3 TriG 4 TriG V2 5 Septentrio PolaRx4TR Pro 6 Ashtech Z-12 7 Javad Delta-3 8 Ashtech uZ-CGRS 9 Javad EGGDT-160

10 Novatel OEM628V-G1S-B0G-TTN-H 11 Javad Delta II 12 Septentrio PolaRx4Pro 13 Trimble NETR5 14 Trimble NETR5 15 Trimble NETR9 16 Leica GRX1200GGPRO 17 Trimble 5700 18 Leica GRX1200GGPRO 19 Trimble NETRS 20 Trimble NETRS

No. Receiver 21 Trimble NETRS 22 Topcon Net-G3A Sigma 23 Garmin GPSMap 295 24 Garmin - GPSMap 696 25 Garmin - Area 560 26 Garmin - GLOGPS (GPS & GLONASS) 27 Dual Electronics - SkyPro XGPS 150 28 EVA-7M EVK-7EVA-0 29 MAX-7C EVK-7C-0 30 MAX-7Q EVK-7N-0 31 EVA-M8M EVK-M8EVA-0 32 LEA-M8F EVK-M8F-0 33 MAX-M8Q EVK-M8N-0 34 LEA-M8S EVK-M8N-0 35 uBlox EVU-6P-0-001 36 SiRF III 37 Trimble NETR5 38 Symmetricom Xli 39 Symmetricom-GPS 40 Trimble SMT360 GPS receiver

Receivers included in the wired/conducted test 20

Receiver Test List (2/2)

No. Receiver 41 Dynon 250 42 Dynon 2020 43 Garmin EDGE 1000 44 Garmin GPSMAP 64 45 Garmin ETREX 20x 46 Garmin FORERUNNER 230 47 Garmin GPSMAP 741 48 Symmetricom Xli 49 JAVAD Triumph-1 50 Hemisphere R330 51 NAVCOM SF3050 52 Symmetricom SyncServer S350 53 Arbiter Systems 1088B 54 Arbiter Systems 1094B 55 Schweitzer Eng. Labs SEL-2401 56 Android S5 57 Android S6 58 Android S7 59 Supercruise "VCP" 60 Supercruise "VCP"

No. Receiver 61 EVK-M8N 62 EVK-M8T 63 MAX-M8Q 64 EVK-7P 65 EVK-6n 66 NovAtel 628 Card w/ Flex pack 67 Trimble Ag-382 68 Trimble Geo 7X 69 Trimble Bison III 70 Trimble R8 71 Trimble SPS985 72 Trimble SPS855 73 Trimble Acutime 360 74 Trimble Ag-382 75 SF3000 76 SF3000 77 Septentrio PolaRx5TR Pro 78 Septentrio PolaRx5TR Pro 79 Trimble NetRS 80 Trimble NETR9

Receivers included in the wired/conducted test 21

Test Grid ←Exit

K0 K2 K4 K6 K8 K10 K12

K1 K3 K5 K7 K9 K11 K13

J6

J5

I0 I2 I4 I6 I8 I10 I12

I1 I3 I5 I7 I9 I11 I13

H8

H7

G0 G2 G4 G6 G8 G10 G12

G1 G3 G5 G7 G9 G11 G13

E0 E2 E4 E6 E8 E10 E12

E1 E3 E5 E7 E9 E11 E13

D8

D7

C0 C2 C4 C6 C8 C10 C12

C1 C3 C5 C7 C9 C11 C13

B6

B5

A0 A2 A4 A6 A8 A10 A12

A1 A3 A5 A7 A9 A11 A13

Note: not drawn to scale

Mezzanine

GM

16

UNAVCO

5

1211

2

4

3

USGS TRIMBLE DEERE

8

106

2

NOVATEL

15

98

UBLOX

7 13

Aero_Spec_A

182

1 2

USDOTUSCG NASA NOAA

3

9

5

FAA

23

22

GNSS Signal Generation and Recording

23

GNSS Signal Playback and Transmission

24

Interference Signal Generation Diagram

25

List of External Antennas Tested

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Manufacturer Model

AeroAntenna AT575-142-614-50

AeroAntenna AT2775-42SYW-TNCF-000-RG-41_MN

Arbiter AS0087800

Garmin GA-25

Garmin GA-38

Hemisphere 804-3059-0

Leica AX1202GG

Navcom 82-001020-3001LF

PCTel 3977D

Trimble Bullet 360 Antenna 101155-10

Trimble Choke Ring 29659-00

Trimble Zephyr 41249-00

Trimble Zephyr Geodetic 2 55971-00

Ublox ANN-MS-0-005